oracular (3) wayland_presentation_t.3.gz
NAME
wayland::presentation_t - timed presentation related wl_surface requests
SYNOPSIS
#include <wayland-client-protocol-extra.hpp>
Inherits wayland::proxy_t.
Public Types
enum class wrapper_type { standard, display, foreign, proxy_wrapper }
Public Member Functions
presentation_feedback_t feedback (surface_t const &surface)
request presentation feedback information
std::function< void(uint32_t)> & on_clock_id ()
clock ID for timestamps
uint32_t get_id () const
Get the id of a proxy object.
std::string get_class () const
Get the interface name (class) of a proxy object.
uint32_t get_version () const
Get the protocol object version of a proxy object.
wrapper_type get_wrapper_type () const
Get the type of a proxy object.
void set_queue (event_queue_t queue)
Assign a proxy to an event queue.
wl_proxy * c_ptr () const
Get a pointer to the underlying C struct.
bool proxy_has_object () const
Check whether this wrapper actually wraps an object.
operator bool () const
Check whether this wrapper actually wraps an object.
bool operator== (const proxy_t &right) const
Check whether two wrappers refer to the same object.
bool operator!= (const proxy_t &right) const
Check whether two wrappers refer to different objects.
void proxy_release ()
Release the wrapped object (if any), making this an empty wrapper.
Static Public Attributes
static constexpr std::uint32_t feedback_since_version = 1
Minimum protocol version required for the feedback function.
Detailed Description
timed presentation related wl_surface requests
The main feature of this interface is accurate presentation timing feedback to ensure smooth video
playback while maintaining audio/video synchronization. Some features use the concept of a presentation
clock, which is defined in the presentation.clock_id event.
A content update for a wl_surface is submitted by a wl_surface.commit request. Request 'feedback'
associates with the wl_surface.commit and provides feedback on the content update, particularly the final
realized presentation time.
Definition at line 76 of file wayland-client-protocol-extra.hpp.
Member Enumeration Documentation
enum class wayland::proxy_t::wrapper_type [strong], [inherited]
Underlying wl_proxy type and properties of a proxy_t that affect construction, destruction, and event
handling
Enumerator
standard
C pointer is a standard type compatible with wl_proxy*. Events are dispatched and it is destructed
when the proxy_t is destructed. User data is set.
display
C pointer is a wl_display*. No events are dispatched, wl_display_disconnect is called when the
proxy_t is destructed. User data is set.
foreign
C pointer is a standard type compatible with wl_proxy*, but another library owns it and it should
not be touched in a way that could affect the operation of the other library. No events are
dispatched, wl_proxy_destroy is not called when the proxy_t is destructed, user data is not
touched. Consequently, there is no reference counting for the proxy_t. Lifetime of such wrappers
should preferably be short to minimize the chance that the owning library decides to destroy the
wl_proxy.
proxy_wrapper
C pointer is a wl_proxy* that was constructed with wl_proxy_create_wrapper. No events are
dispatched, wl_proxy_wrapper_destroy is called when the proxy_t is destroyed. Reference counting
is active. A reference to the proxy_t creating this proxy wrapper is held to extend its lifetime
until after the proxy wrapper is destroyed.
Definition at line 116 of file wayland-client.hpp.
Member Function Documentation
wl_proxy * wayland::proxy_t::c_ptr () const [inherited]
Get a pointer to the underlying C struct.
Returns
The underlying wl_proxy wrapped by this proxy_t if it exists, otherwise an exception is thrown
presentation_feedback_t presentation_t::feedback (surface_t const & surface)
request presentation feedback information
Returns
new feedback object
Parameters
surface target surface
Request presentation feedback for the current content submission on the given surface. This creates a new
presentation_feedback object, which will deliver the feedback information once. If multiple
presentation_feedback objects are created for the same submission, they will all deliver the same
information.
For details on what information is returned, see the presentation_feedback interface.
Definition at line 720 of file wayland-client-protocol-extra.cpp.
std::string wayland::proxy_t::get_class () const [inherited]
Get the interface name (class) of a proxy object.
Returns
The interface name of the object associated with the proxy
uint32_t wayland::proxy_t::get_id () const [inherited]
Get the id of a proxy object.
Returns
The id the object associated with the proxy
uint32_t wayland::proxy_t::get_version () const [inherited]
Get the protocol object version of a proxy object. Gets the protocol object version of a proxy object, or
0 if the proxy was created with unversioned API.
A returned value of 0 means that no version information is available, so the caller must make safe
assumptions about the object's real version.
display_t will always return version 0.
Returns
The protocol object version of the proxy or 0
wrapper_type wayland::proxy_t::get_wrapper_type () const [inline], [inherited]
Get the type of a proxy object.
Definition at line 302 of file wayland-client.hpp.
std::function< void(uint32_t)> & presentation_t::on_clock_id ()
clock ID for timestamps
Parameters
clk_id platform clock identifier
This event tells the client in which clock domain the compositor interprets the timestamps used by the
presentation extension. This clock is called the presentation clock.
The compositor sends this event when the client binds to the presentation interface. The presentation
clock does not change during the lifetime of the client connection.
The clock identifier is platform dependent. On Linux/glibc, the identifier value is one of the clockid_t
values accepted by clock_gettime(). clock_gettime() is defined by POSIX.1-2001.
Timestamps in this clock domain are expressed as tv_sec_hi, tv_sec_lo, tv_nsec triples, each component
being an unsigned 32-bit value. Whole seconds are in tv_sec which is a 64-bit value combined from
tv_sec_hi and tv_sec_lo, and the additional fractional part in tv_nsec as nanoseconds. Hence, for valid
timestamps tv_nsec must be in [0, 999999999].
Note that clock_id applies only to the presentation clock, and implies nothing about e.g. the timestamps
used in the Wayland core protocol input events.
Compositors should prefer a clock which does not jump and is not slewed e.g. by NTP. The absolute value
of the clock is irrelevant. Precision of one millisecond or better is recommended. Clients must be able
to query the current clock value directly, not by asking the compositor.
Definition at line 727 of file wayland-client-protocol-extra.cpp.
wayland::proxy_t::operator bool () const [inherited]
Check whether this wrapper actually wraps an object.
Returns
true if there is an underlying object, false if this wrapper is empty
bool wayland::proxy_t::operator!= (const proxy_t & right) const [inherited]
Check whether two wrappers refer to different objects.
bool wayland::proxy_t::operator== (const proxy_t & right) const [inherited]
Check whether two wrappers refer to the same object.
bool wayland::proxy_t::proxy_has_object () const [inherited]
Check whether this wrapper actually wraps an object.
Returns
true if there is an underlying object, false if this wrapper is empty
void wayland::proxy_t::proxy_release () [inherited]
Release the wrapped object (if any), making this an empty wrapper. Note that display_t instances cannot
be released this way. Attempts to do so are ignored.
Examples
foreign_display.cpp.
void wayland::proxy_t::set_queue (event_queue_t queue) [inherited]
Assign a proxy to an event queue.
Parameters
queue The event queue that will handle this proxy
Assign proxy to event queue. Events coming from proxy will be queued in queue instead of the display's
main queue.
See also: display_t::dispatch_queue().
Examples
proxy_wrapper.cpp.
Member Data Documentation
constexpr std::uint32_t wayland::presentation_t::feedback_since_version = 1 [static], [constexpr]
Minimum protocol version required for the feedback function.
Definition at line 117 of file wayland-client-protocol-extra.hpp.
Author
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